Low-dose Computed Tomography (CT) for the Diagnosis of Congenital Heart Disease in Children: A Meta-analysis

Use of ionizing radiation in a Norwegian cohort of children with congenital heart disease: imaging frequency and radiation dose for the Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) study

BACKGROUND

The European-funded Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) project is a multicenter cohort study assessing the long-term effects of ionizing radiation in patients with congenital heart disease. Knowledge is lacking regarding the use of ionizing radiation from sources other than cardiac catheterization in this cohort.

OBJECTIVE

This study aims to assess imaging frequency and radiation dose (excluding cardiac catheterization) to patients from a single center participating in the Norwegian HARMONIC project.

MATERIALS AND METHODS

Between 2000 and 2020, we recruited 3,609 patients treated for congenital heart disease (age < 18 years), with 33,768 examinations categorized by modality and body region. Data were retrieved from the radiology information system. Effective doses were estimated using International Commission on Radiological Protection Publication 60 conversion factors, and the analysis was stratified into six age categories: newborn; 1 year, 5 years, 10 years, 15 years, and late adolescence.

RESULTS

The examination distribution was as follows: 91.0% conventional radiography, 4.0% computed tomography (CT), 3.6% diagnostic fluoroscopy, 1.2% nuclear medicine, and 0.3% noncardiac intervention. In the newborn to 15 years age categories, 4-12% had ≥ ten conventional radiography studies, 1-8% underwent CT, and 0.3-2.5% received nuclear medicine examinations. The median effective dose ranged from 0.008-0.02 mSv and from 0.76-3.47 mSv for thoracic conventional radiography and thoracic CT, respectively. The total effective dose burden from thoracic conventional radiography ranged between 28-65% of the dose burden from thoracic CT in various age categories (40% for all ages combined). The median effective dose for nuclear medicine lung perfusion was 0.6-0.86 mSv and for gastrointestinal fluoroscopy 0.17-0.27 mSv. Because of their low frequency, these procedures contributed less to the total effective dose than thoracic radiography.

CONCLUSION

This study shows that CT made the largest contribution to the radiation dose from imaging (excluding cardiac intervention). However, although the dose per conventional radiograph was low, the large number of examinations resulted in a substantial total effective dose. Therefore, it is important to consider the frequency of conventional radiography while calculating cumulative dose for individuals. The findings of this study will help the HARMONIC project to improve risk assessment by minimizing the uncertainty associated with cumulative dose calculations.

How Does Cross-Sectional Imaging Impact the Management of Patients With Single Ventricle After Bidirectional Cavopulmonary Connection?

BACKGROUND

There is currently no consensus regarding the use of surveillance cross-sectional imaging in pediatric patients after bidirectional cavopulmonary connection (BDCPC). We sought to determine how computed tomography with angiography (CTA) and cardiac magnetic resonance (CMR) imaging impacted the clinical management of pediatric patients after BDCPC.

METHODS

A single-center retrospective study including patients with single ventricle who had BDCPC between 2010 and 2019, and CTA/CMR studies obtained in these patients, at ≤5 years of age, and with Glenn physiology. Repeat studies on the same patient were included if the clinical situation had changed. The impact of CTA/CMR studies was categorized as major, minor, or none.

RESULTS

Twenty-four patients (63% male) and 30 imaging studies (22 CTAs) were included. 60% were obtained in patients with hypoplastic left heart syndrome (HLHS); most common indication was Follow-up after an intervention (23%). 6 CMRs were performed on stable HLHS patients as part of a research protocol, with no clinical concerns. The overall impact of CTA/CMR studies was major in 13 cases (43.3%). CTA/CMR studies performed ≥1 year of age (62.5% vs 21.4%, P = .02) and in non-HLHS patients (66.7% vs 27.8%, P = .035) were associated with major impact. Also, 2/6 Research studies were associated with a major impact.

CONCLUSIONS

CTA/CMR imaging in pediatric patients with SV after BDCPC was associated with significant clinical impact in over 40% of cases, with a higher impact if obtained in patients ≥1 year of age and in non-HLHS patients. We cannot disregard the possibility of CMR as a surveillance imaging modality in this population.

SIRM-SIC appropriateness criteria for the use of Cardiac Computed Tomography. Part 1: Congenital heart diseases, primary prevention, risk assessment before surgery, suspected CAD in symptomatic patients, plaque and epicardial adipose tissue characterization, and functional assessment of stenosis

In the past 20 years, Cardiac Computed Tomography (CCT) has become a pivotal technique for the noninvasive diagnostic work-up of coronary and cardiac diseases. Continuous technical and methodological improvements, combined with fast growing scientific evidence, have progressively expanded the clinical role of CCT. Recent large multicenter randomized clinical trials documented the high prognostic value of CCT and its capability to increase the cost-effectiveness of the management of patients with suspected CAD. In the meantime, CCT, initially perceived as a simple non-invasive technique for studying coronary anatomy, has transformed into a multiparametric "one-stop-shop" approach able to investigate the heart in a comprehensive way, including functional, structural and pathophysiological biomarkers. In this complex and revolutionary scenario, it is urgently needed to provide an updated guide for the appropriate use of CCT in different clinical settings. This manuscript, endorsed by the Italian Society of Medical and Interventional Radiology (SIRM) and by the Italian Society of Cardiology (SIC), represents the first of two consensus documents collecting the expert opinion of Radiologists and Cardiologists about current appropriate use of CCT.